In general, a dryer is a machine for drying laundry by supplying heated air to laundry.
The air discharged to an outside of the drum from the inside of the drum after heat exchange with the laundry absorbs moisture from the laundry in the drum, to become humid and high temperature air. The dryer may be classified as follows.
For example, an exhaust type dryer discharges humid and high temperature air from the drum to the outside of the dryer, while a condensing type dryer, in which a heat exchanger condenses and heats the air from the drum during operation, re-supplies the humid and high temperature air to the drum (i.e., recirculates the air discharged from the drum).
In general, the air being discharged from the drum during drying may contain foreign matter, such as lint or the like, from the object being dried, such as clothes. The foreign matter can damage the dryer if accumulated on elements of the dryer, can also pollute air by discharging foreign matter to the outside of the dryer. Therefore, the dryer is required to remove the foreign matter from the air that is being discharged from the drum.
In general, a filter provided to the dryer is positioned on a front of the drum for filtering the foreign matter from the air being discharged from the drum. Accordingly, if the dryer is used continuously, the filter has the foreign matter, such as lint, accumulated thereon.
If the accumulation of the foreign substance on the filter becomes greater than a preset level, the foreign substance can interfere with the discharge of the air from the drum; thus, the filter in the dryer should be cleaned periodically. The filter cleaning is carried out as the user separates the filter from the dryer after finishing a drying cycle, and removes the foreign matter from the filter.
However, such filter cleaning carried out manually may not only be cumbersome but also, because the filter cleaning may not be carried out every time the dryer is operated, can lead to, until the filter is cleaned, a failure to secure adequate air flow rate required for drying due to the foreign substance interfering with the air flow being discharged from the drum.